Field of the Invention
The present invention relates to a pneumatic tire which can reduce cavernous resonance sound by attaching a plate-like member to an inner surface of a tread portion.
Description of the Related Art
In the case that a vehicle travels on a rough road surface or climbs over a joint of the road surface, noise that is road noise may be generated in a vehicle. The road noise is one of the noise which has a relation with the tire. In the case that the tire is vibrated by receiving the irregularities of the road surface, the cavernous resonance sound is energized in an inner portion of the tire by the vibration, and the noise in the vehicle is caused.
In Patent Document 1, there is described a pneumatic tire in which a sound control material made of a sponge material is arranged in a tire inner cavity surrounded by a rim and the pneumatic tire, for the purpose of reducing the road noise. However, the sponge material mentioned above is in danger of increasing a whole weight of the tire so as to cause deterioration of fuel consumption. Further, there is a problem of causing an increase of cost since a large number of sponge materials are required.
In Patent Document 2, there is described a pneumatic tire in which a partition wall partitioning an interior of an air chamber in a circumferential direction is provided within the air chamber which is formed between a tire inner peripheral surface and a rim outer peripheral surface, for the purpose of preventing deterioration of the road noise while suppressing a great cost increase. An equivalent length of an air column within the air chamber becomes shorter by using the partition wall to partition the interior of the air chamber in the circumferential direction, so that resonant frequency of air column resonance can be shifted, thereby preventing deterioration of the road noise due to the air column resonance.
Further, in Patent Document 3, there is provided a pneumatic tire in which a thin elastic divider plate extending approximately in an axial direction within a tire inner cavity is provided in an inner wall of the tire, for the purpose of reducing road noise caused by cavernous resonance sound while suppressing an increase in weight. A whole sound pressure mode within the tire inner cavity changes and an in-vehicle noise level is reduced, by the provision of the elastic divider plate within the tire inner cavity.
However, the partition wall and the divider plate vibrate by themselves and may deteriorate the road noise due to the cavernous resonance sound as a new sound source.